It's not all that easy to see, but here's where my HID ballast are
on this one, if you look near the bottom of the picture you will see the back (rear) of the headlamp assembly. The cover that conceals the bulbs inside the headlamp unit needs holes in it to accommodate the larger sized wiring from the HID unit. Hope this is more helpful, than confusing.
This applies to almost all installations on any vehicles that have a headlight cap without holes already. You may want to browse our installation guides to see other vehicle's installs as all installs are essentially the same. http://store.sharphid.com/category_s/136.htm